#include<bits/stdc++.h> #define FOR(i,a,b) for(int i=(a);i<(b);++i) #define FORD(i, a, b) for(int i = (a); i >= (b); --i) #define VAR(v, i) __typeof(i) v=(i) #define FORE(i, c) for(VAR(i, (c).begin()); i != (c).end(); ++i) #define VI vector<int> #define PII pair<int,int> #define st first #define nd second #define mp make_pair #define pb push_back #define lint long long int #define debug(x) {cerr <<#x <<" = " <<x <<endl; } #define debug2(x,y) {cerr <<#x <<" = " <<x << ", "<<#y<<" = "<< y <<endl; } #define debug3(x,y,z) {cerr <<#x <<" = " <<x << ", "<<#y<<" = "<< y << ", " << #z << " = " << z <<endl; } #define debugv(x) {{cerr <<#x <<" = "; FORE(itt, (x)) cerr <<*itt <<", "; cerr <<endl; }} #define debugt(t,n) {{cerr <<#t <<" = "; FOR(it,0,(n)) cerr <<t[it] <<", "; cerr <<endl; }} #define make( x) int (x); scanf("%d",&(x)); #define make2( x, y) int (x), (y); scanf("%d%d",&(x),&(y)); #define make3(x, y, z) int (x), (y), (z); scanf("%d%d%d",&(x),&(y),&(z)); #define make4(x, y, z, t) int (x), (y), (z), (t); scanf("%d%d%d%d",&(x),&(y),&(z),&(t)); #define IOS ios_base::sync_with_stdio(0) #define HEAP priority_queue #define read( x) scanf("%d",&(x)); #define read2( x, y) scanf("%d%d",&(x),&(y)); #define read3(x, y, z) scanf("%d%d%d",&(x),&(y),&(z)); #define read4(x, y, z, t) scanf("%d%d%d%d",&(x),&(y),&(z),&(t)); using namespace std; int n; int mod = 998244353; char s[50005]; int dp[50005]; int last[10]; int od_ost[10][10]; void doit() { FOR(i,0,6) last[i] = -1; FOR(i,0,6) FOR(j,0,6) od_ost[i][j] = -1; dp[0] = 1; FOR(i,1,n+1) { dp[i] = 2 * dp[i-1]; int lst = last[s[i-1]-'a']; if (lst != -1) { dp[i] = dp[i] - dp[lst]; } last[s[i-1]-'a'] = i - 1; if (dp[i] < 0) dp[i] += mod; if (dp[i] >= mod) dp[i] -= mod; } int TOTAL = dp[n] - 1; //cout << "TOTAL " << TOTAL << endl; dp[0] = 1; FOR(i,0,6) { od_ost[i][s[0]-'a'] = 0; } FOR(i,1,n) { int ja = s[i]-'a'; dp[i] = 0; if (od_ost[ja][ja] == -1) dp[i] = 1; FOR(j,0,6) { if (od_ost[ja][j] != -1) dp[i] = (dp[i] + dp[od_ost[ja][j]]) % mod; } FOR(j,0,6) { od_ost[ja][j] = -1; od_ost[j][ja] = i; } } /* FOR(i,0,n) { cout << dp[i] << " " ; } cout << endl; */ int UNIQUE = 0; FOR(j,0,6) { if (od_ost[j][j] != -1) UNIQUE = (UNIQUE + dp[od_ost[j][j]]) % mod; } // cout << "UNIQUE : " << UNIQUE << endl; int res = (TOTAL - UNIQUE + mod)%mod; printf("%d\n", res); } void solve() { read(n); make(q); scanf("%s", s); doit(); FOR(i,0,q) { make(pos); pos--; char C = 'A'; while (C<'a' || C > 'f') C = getchar(); s[pos] = C; doit(); } } int main() { solve(); }
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 | #include<bits/stdc++.h> #define FOR(i,a,b) for(int i=(a);i<(b);++i) #define FORD(i, a, b) for(int i = (a); i >= (b); --i) #define VAR(v, i) __typeof(i) v=(i) #define FORE(i, c) for(VAR(i, (c).begin()); i != (c).end(); ++i) #define VI vector<int> #define PII pair<int,int> #define st first #define nd second #define mp make_pair #define pb push_back #define lint long long int #define debug(x) {cerr <<#x <<" = " <<x <<endl; } #define debug2(x,y) {cerr <<#x <<" = " <<x << ", "<<#y<<" = "<< y <<endl; } #define debug3(x,y,z) {cerr <<#x <<" = " <<x << ", "<<#y<<" = "<< y << ", " << #z << " = " << z <<endl; } #define debugv(x) {{cerr <<#x <<" = "; FORE(itt, (x)) cerr <<*itt <<", "; cerr <<endl; }} #define debugt(t,n) {{cerr <<#t <<" = "; FOR(it,0,(n)) cerr <<t[it] <<", "; cerr <<endl; }} #define make( x) int (x); scanf("%d",&(x)); #define make2( x, y) int (x), (y); scanf("%d%d",&(x),&(y)); #define make3(x, y, z) int (x), (y), (z); scanf("%d%d%d",&(x),&(y),&(z)); #define make4(x, y, z, t) int (x), (y), (z), (t); scanf("%d%d%d%d",&(x),&(y),&(z),&(t)); #define IOS ios_base::sync_with_stdio(0) #define HEAP priority_queue #define read( x) scanf("%d",&(x)); #define read2( x, y) scanf("%d%d",&(x),&(y)); #define read3(x, y, z) scanf("%d%d%d",&(x),&(y),&(z)); #define read4(x, y, z, t) scanf("%d%d%d%d",&(x),&(y),&(z),&(t)); using namespace std; int n; int mod = 998244353; char s[50005]; int dp[50005]; int last[10]; int od_ost[10][10]; void doit() { FOR(i,0,6) last[i] = -1; FOR(i,0,6) FOR(j,0,6) od_ost[i][j] = -1; dp[0] = 1; FOR(i,1,n+1) { dp[i] = 2 * dp[i-1]; int lst = last[s[i-1]-'a']; if (lst != -1) { dp[i] = dp[i] - dp[lst]; } last[s[i-1]-'a'] = i - 1; if (dp[i] < 0) dp[i] += mod; if (dp[i] >= mod) dp[i] -= mod; } int TOTAL = dp[n] - 1; //cout << "TOTAL " << TOTAL << endl; dp[0] = 1; FOR(i,0,6) { od_ost[i][s[0]-'a'] = 0; } FOR(i,1,n) { int ja = s[i]-'a'; dp[i] = 0; if (od_ost[ja][ja] == -1) dp[i] = 1; FOR(j,0,6) { if (od_ost[ja][j] != -1) dp[i] = (dp[i] + dp[od_ost[ja][j]]) % mod; } FOR(j,0,6) { od_ost[ja][j] = -1; od_ost[j][ja] = i; } } /* FOR(i,0,n) { cout << dp[i] << " " ; } cout << endl; */ int UNIQUE = 0; FOR(j,0,6) { if (od_ost[j][j] != -1) UNIQUE = (UNIQUE + dp[od_ost[j][j]]) % mod; } // cout << "UNIQUE : " << UNIQUE << endl; int res = (TOTAL - UNIQUE + mod)%mod; printf("%d\n", res); } void solve() { read(n); make(q); scanf("%s", s); doit(); FOR(i,0,q) { make(pos); pos--; char C = 'A'; while (C<'a' || C > 'f') C = getchar(); s[pos] = C; doit(); } } int main() { solve(); } |